Nozzle



Feb. 15 1944. M. L. EDWARDS 2,341,859

NOZZLE Original Filed July 4, 1939 INVENTOR I i v I I Patented Feb. 15, 1944 2,841,859 NOZZLE Miles Lowell Edwards, Longview,

to Weyerhaeuser Wash ' Original application Wash, ueignor Timber Company, Longview. a corporation oi Washington July 4, 1939, Serial No.

Divided and this 1941, Serial No.

application Septem- 412J52 Claims. (01. 299-143) This invention relates to fluid nozzles, and particularly to nozzles from ducing a sharp cutting edge at a relatively great distance from the nozzle. More especially, the invention relates to .nozzles adapted for use in removing bark from logs; this application being removing bark from logs.

According to the method disclosed in the above copending application, bark is removed from logs by forming a fiat, high jet of water and jet of water. capable of producing a relatively sharp cutting or abrasive action at the place of impact.

A further object of the invention is to provide a nozzle which will deliver a high velocity jet of water capable of exerting a highly concentrated force at the place of impact.

A further object of the invention is to provide a nozzle which will deliver an intact stream havin the accompanying drawing, and embraced within the scope of the appended claims.

In the drawing:

Figure l is an end view of a nozzle constructed according to the present invention, and showing its outlet end.

Figure 2 is a longitudinal sectional view 01' the nozzle, taken on the line 22 of Figure 1.

Figure 3 is a longitudinal sectional view, taken on the line 33 of Figure 1.

Figure 4 is a transverse sectional view, taken on the line 4-4 of Figure 2.

Figure 5 is a perspective sectional view of the nozzle, showing the form of the fluid delivery passage.

Figure 6 is a sectional view through a log being operated upon in the manner described in my copending application, illustrating the manner in which a plurality of jets of the type illustrated in Figure 8 may be directed simultaneously in edge to edge relationship against the surface of the log.

Figure 7 is an edge view of rected upon a surface.

The nozzle shown in or header (not shown), by the threaded stem or end 3. The exterior of the forward portion of the body I is machined hexagonally for conveni:

and at least that portion nearest the outlet orifice decreases at a substantially uniform or slightly diminlshingrate so that there will be a minimum of turbulence in the issuing stream. It is important, for the purposes of the present invention, that the outlet orifice be slightly oval in lence in the issuing jet.

In the nozzle of the illustrated embodiment the fluid passageway 2 is of a generally oval cross sectional shape and is capable of forming a. thin,

sectional shaped fluid passage of the nozzle is formed by the convergence of conjoined or overlapping bores, each of which corresponds in shape to the frustum of a simple circular cone, and so decreases in cross sectional area uniformly throughout the length of the nozzle. In the particular modification of the nozzle illustrated, the bores have a taper of approximately 5, while the bores converge at an angle of approximately between center lines of the respective bores, as indicated by the angle a in Figure 3. The center lines of the bores intersect with the axis of the nozzle at a point D located at a distance from the end of the nozzle substantially equal to the length of the short axis of the oval orifice. This distance is not critical but may vary somewhat depending upon the angle of taper of the two bores and the angular relation of their center lines. The distance must be finite, however, in order to impart said generally oval shape to the orifice, it being understood that if it were zero, the orifice would be circular in cross sectional shape. Withbores of the taper and angular relationship stated above, the point D of intersection of the center lines is spaced from the end of the nozzle a distance approximately equal to the length of the short axis of the oval orifice 4 in the end of the nozzle. It will be observed that the apices of the extended surfaces of the two tapered bores, indicated at 0, lie farther from the end of the nozzle than the point I). This is due to the fact that the passage is of decreasing eccentricity from the inlet to the outlet, the eccentricity of the bores at the inlet end, as illustrated in Figure 4, being of the order of seventy-five percent. While the drawing shows the amount of overlap at the inlet end as being less than at the outlet end, it will be obvious that the amount of overlap of the tapered bores at the inlet end may be the same as that occurring at the outlet end and hence be constant throughout the length of the nozzle passage. In this instance the eccentricity of the passage cross section will be constant and everywhere correspond with that of the orifice, and points b and 0 will be common although spaced from the end of the nozzle. While in the illustrated modification the passageway is not, in a strict sense, oval shaped in cross section throughout its, length, due to slight longitudinal ridges at the intersection of the tapered bore surfaces, however, the presence of these ridges has substantially no effect in the formation of the jets, particularly since they Dractically disappear at the orifice end.

The mouth of the nozzle is reamed so as to provide a smooth conical approach to the passageway as indicated at l2. The outer diameter of the conical reamed portion corresponds substantially to the maximum cross sectional dimension of the oval passageway, but the taper thereof is much greater than the bores forming the main fluid channel. For all practical purposes, therefore, the fluid passage 2 may be considered to be generally oval in cross section throughout its principal length, and to be progressively decreasing in cross sectional area.

In Figure 8 is shown the character of the stream projected by the nozzle. The stream issuing from the orifice 4 is in the form of a solid body of liquid slightly oval in cross section. Upon advancing away from the nozzle, the stream develops into aflat, uniform, coherent sheet of water, the plane of which is at right angles to the long axis of the oval shaped nozzle orifice.

While there is a tendency for the flattened let portion to fan outwardly, the angle of divergence is relatively small so that even at a considerable distance from the nozzle the jet is maintained relatively narrow. This feature is important for numerous reasons. One reason is that the percentage of loss of kinetic energy of the let in passing through the air is thereby minimized. Consider first a case in which the let is allowed to fan out with a considerably large angle. It will be obvious that the coherency of the sheet of water is then terminated at a relatively short distance from the nozzle and the flow will break up into a plurality of separated streams, which further will subdivide into a spray of minute droplets. The kinetic energy of the jet will be lost rapidly, due to the frictional resistance between each droplet and the air, and little of the original total-amount of energy will be available for effective work at the surface of impact. The nozzle of the invention, on the other hand, maintains the flow consolidated in a solid stream whereby a minimum of water surface is in contact with air so that the frictional resistance therebetween is low and comparatively little of the jet energy is lost. Another reason is that the water particles of the jet produced by the instant nozzle diverge with a relatively slight angle so that a maximum amount of work is performed on the surface. Assume again a wide angle fan shaped jet of water directed against a plane surface which is to be cleaned and in a plane perpendicular to such surface. Only the central portion of the let will impinge against the surface from a direction at right angles with respect thereto and expend a maximum of energy thereupon. On opposite sides from the center the angle of impact decreases progressively from ninety degrees and consequently progressively smaller proportions of the kinetic energy of the water particles is expended at the surface. At the extreme outer edges, the water particles merely strike the surface with a o glancing blow and are deflected with a very slight energy loss and hence little useful work is performed. In the jet from the nozzle of the present invention the angle of fan is restricted to a very low value, for example, of the order of ten degrees, or less, so that even at the outermost edges the water particles strike the surface at an angle of at least degrees. Thus it will be apparent that the water particles of the let from the instant nozzle travel in slightly divergent lines and consequently perform a maximum of work at the surface of impact.

The nozzle of the present invention is particularly suitable for removing bark from logs and for which purpose it may be arranged at a distance of from fifteen to twenty inches and at which distance the thin cutting edge of the stream will be relatively narrow, for example, of the order of four inches in width. The let is directed approximately perpendicularly toward the surface of the log to obtain the greatest mechanical reaction thereagainst and thereby exert the greatest erosive action on the bark. It will readily be understood that logs of mill run varieties are frequently crooked and cannot be so supported that the surface throughout the log length is uniformly spaced from the path of travel of the nozzle. Jets of water from nozzles of the present invention, however, are eflicieni over a relatively long portion of their length sc that a complete removal of bark is effected ever high pressure, for example, 1200 pounds per square inch, the water is rojected from the traveling header by means of nozzles 9, one or more of which may be employed, as may be desired. Where more than one nozzle is employed, each is so mounted with respect to the others that the jets of water projected thereby are delivered in edge to edge relation to produce the efiect of a single wide sheet of water at right angles to the longitudinal axis of the log Hi. The several jets of water produced by the nozzles 9 are in alignment transversely of the log, and coact to remove a strip of bark from the log as wide as the combined width of the several jets.

jets are radially directed against the log.

Although there is herein illustrated and despirit and scope of the appended way and diminishing as it orifice of the nozzle.

tially mately 15 degrees at a point beyond the outletorifice of the nozzle.

3. A nozzle having a fluid passageway of progressively decreasing cross sectional area. and

formed by the convergence of two similar overlapping bores having a taper of about five deorifice and degrees.

4. A nozzle having a fluid passageway substantially oval in cross sectional shape throughout diminishing of the nozzle.

nozzle. 6. A fluid nozzle substantially oval in cross sectional shape g to approxijacent the inlet end.

9. A nozzle having a fluid passageway defined by two overlapping similar secting therebeyond.

10. A nozzle having a fluid passageway defined by two overlapping similar tapered bores, the center lines of said bores intersecting at a. point spaced from the outlet end of said nozzle by a distance substantially equal to the cross sectional dimension of the outlet orifice along its short axis.

MILES LOWELL EDWARDS. I 

